1. Introduction to C#
AKEEL AHMED

2. What is .NET? A Framework in which to run code
A Common Language Runtime (CLR)
runs all programs
C# compiles to Microsoft Intermediate Language
MSIL runs on CLR
Virtual Machine like Java
code written in many languages compiles to MSIL
A Common Language Specification (CLS)
A Common Type System (CTS)

3. Building Blocks (e.g. for Services)
What is .NET?
Runtime
Operating System
.NET Framework
Common
Type
System
Language
Building Blocks (e.g. for Services)
Services: .NET and COM+
SQL Server
BizTalk
...
Languages:
C#, Visual Basic, etc
.NET Applications
Enterprise Servers
Sharepoint
Web Services
From MSDN

4. Base Class Library Support
What is the CLR?
Class Loader
MSIL to Native
Compilers (JIT)
Code
Manager
Garbage
Collector (GC)
Security Engine
Debug Engine
Type Checker
Exception Manager
Thread Support
COM Marshaler
Base Class Library Support
From MSDN

5. What is the CTS? A set of common types For example
any language that runs in CLR should implement
no syntax specified
Languages often define aliases
For example
CTS defines System.Int32 – 4 byte integer
C# defines int as an alias of System.Int32

6. What is the CTS?
From MSDN

7. What is the CLS? A specification of language features For example
how methods may be called
when constructors are called
subset of the types in CTS are allowed
For example
Code that takes UInt32 in a public method
UInt32 is not in the CLS
Can mark classes as CLS-compliant
not marked is assumed to mean not compliant

8. The Class Libraries The common classes used in many programs
like Java Class Library
eg.
System.Console.WriteLine
XML, Networking, Filesystem, Crypto, containers
Can inherit from many of these classes
Many languages run on .NET framework
C#, C++, J#, Visual Basic
even have Python (see IronPython)

9. Assemblies Code contained in files called “assemblies”
code and metadata
.dll( daynamic link library) as before
to run: public static void Main(string[] args)
types
private: local directory, not accessible by others
eg. Wolfram .NETLink
shared: well-known location
strong names: use crypto for signatures
then can add some versioning and trust

10. First C# Program using System; namespace Test { int a = 137;
class Hello { public static void Main(string[] args) { Console.WriteLine(“Hello {0}”, a); } } }

11. Constructions of Note using namespace class
like import in Java: bring in namespaces
namespace
disambiguation of names
like Internet hierarchical names and Java naming
class
like in Java
single inheritance up to object

12. Constructions of Note Console.Write(Line)
Takes a formatted string: “Composite Format”
Indexed elements: e.g., {0}
can be used multiple times
only evaluated once
{index [,alignment][:formatting]}
also can use as in Java
“Test “ + a